Answer:
4.97 X 10^13 ATOMS OF Zn
Explanation:
how many atoms of zinc are required to weigh 5.4 ng
a nano gram is 10^-9 grams
Zinc has an atomic mass of 65.39 gm/moles
there is an Avogadros number of atoms in a mole
65.39 GRAMS PER MOLE
65.39 g/(6.022 X 10^23)how many atoms of zinc are required to weigh 5.4 ng
GRAMS PER ATOM
1.086 GRAMS PER 1O^22 ATOMS
1 atom of Zn weighs 1.086 X 10^9 X 1O^-22 n grm=
1,086 X 10^-13 n gm
Y tines 1.086 X 10^-13 = 5.4 n gm
Y = 5.4/ (1.086 X 10^-13) =
4.97 X 10^13 ATOMS OF Zn
CHECK
(4.97 X 10^13 ) X 65.39 gm/(6.022 X 10^23) =
5.397 X 10^-9 =
5.4 n g
